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t=1792484831; bh=hD3QL3zhfQaS6wp7jLt510z1yjbpvqOBC7skF7FHaiI=; h=Date:Subject:To:Cc:References:From:In-Reply-To; b=lbURHUqCrjNtQgm+44XHMvS7UGgRz+SSQQZJJLmZuwjLS97fVgLwmQWtDCVavLsmH JPaxgW/Tpul+eM7S4xmoAFTri7OYweN7ymjGQZ7jaUiJnr0gRJnJqPNWpUFrRbr5mv +tGxmN9wRb/xhBtz2aeD2fBjPYX/7x6BPgGPIF3eEZDIQQxNxs+VHzowVHiiCkzCVo gSzGfeD1Gyhr0OoTiNp6YB10sl9vS9aiXNchWAayP+qgKQJGkQcR+HbrLTaNeQJwXe 91islngKr8L+2HJJELjTBFsB5TqTIQ9HEULpZhuJlm/5DaJxmYJHEu+zWsS8pKZYdS ivwBIsBrrUpQw== Message-ID: <3a034d40-e01d-42cf-9325-8c1e4a6db1b9@kernel.org> Date: Tue, 20 Oct 2026 10:27:07 +0200 X-Archived-By: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH v1] mempool: fix min_nr exceeding the elements array after concurrent resizes Content-Language: en-US To: Vitaly Wool , Harry Yoo Cc: akpm@linux-foundation.org, cl@gentwo.org, hao.li@linux.dev, hch@lst.de, linux-kernel@vger.kernel.org, linux-mm@kvack.org, nickolai@csail.mit.edu, rientjes@google.com, roman.gushchin@linux.dev, vitaly.vul@partner.samsung.com References: <20261018160315.1465504-1-vitaly.wool@konsulko.se> From: "Vlastimil Babka (SUSE)" Autocrypt: addr=vbabka@kernel.org; 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charset=UTF-8 Content-Transfer-Encoding: 8bit X-Rspam-User: X-Rspamd-Queue-Id: 545D540007 X-Stat-Signature: 1pzgmk93h8k4ruufpmcipkcwaa8z1ihw X-Rspamd-Server: rspam01 X-Spam-Status: No, score=-7.6 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_HELO_PASS,SPF_PASS,USER_AGENT_SANE_1 autolearn=no autolearn_force=no version=4.0.1 X-HE-Tag: 1792484832-923015 X-HE-Meta: U2FsdGVkX18xLPMZtnERM7aQsWiK15k3k1svYnJcvnmWah8+Ozllgf42HRSmj/6dMAn4wpwQH3T+62BrdovPpiqreObKaehyza8uYTfHl0RblE5bzfTUi2ef3+LzHSbFBiB6RfUBA1oI5Wg0XIX4tYzBt+yji/HmptpbTp/nqzg65/O09AhHk1YnjaW8QHMwGthVN2n7TI3nNylBDQEGgmr0s/TShlQw6ntoykeHunjCk+bE6rQaNigFQFJZnKrTEpldZVkz75vgULRiEZHrbFidtmc6ajb9xCq88PfNQVDQd/ycBn9J/pSkZWMGHurl0XGs/G/GQ4S4iAI7xtfK8x6QsIsRtPJsrxrM09KqbPlehAs+vBF/RbXMYjxDZPSUKojqKDxwAvE10mloYznonRL1N+iRHPOW6oarG0UzIHp6GOaHVOpIRwGUmDPxRWLWwXo6MtGsbXI76arzC+0x8WemC3LAs6iUY1QhHy9CXsatQk3+1FFMTsnMDmot73QOxYdcrngmWdRZ4bYp4itNqD1ZepImjYz4dOW9Sx61+Rd3japBoVZU23ZkDqH9ga9OBx27nTlUaxU2LkLQkyFKZ9EuJiihj2MJYCblDj5TtsMCDEiGQjePLsgahjF156Yt3FUYX2jwOKop3DI/i4/Z5PiFh5tzxzeHh3q0z7LEtAgXEmeBNKd15INQsUQUmXioMC2Y+tOFvAcapkAjgAsOZ6KmfSCidkR4/7mFpr4Kjx1OR6+WAt8buKDCXhayza1ajyEdyxirGJqAbIhWlalRkEW0TLj1HobA3ivCpUzUmLTWajebPlj7k6VyuVvb1E0TzKqhy2xHi2m7g9Q4GUrNhzWTnLAjWp5LdZfmqY0xu3N/uRGMvwydKGR/yyDpTZBfKVjnBVQaKPK4f3PSgH4jK066aT7mbQmPm3AFBifcrkD/eP9zHbAJo8kxhR/YNlkIjh4oOqYGCIQoNbsfJ5z DbMf0j3e L7zMn48iAfYo9e/38RFp/7wN0gZo2BsHdofHZUXzfrEYGgZJn/CYEjy6ehiRhXJRwcVi5WjKzY4d/nFhYefHIxIsP5zGIFJm8OhBE5mrJqldWEQaYpcVoX8zmhgy+P6dZEpveGEfd1ZrP8IkPM8v4dYakRGagCTW8lFnS1l3N0OW//u3UsR45a+CkTgQPjLhjKo7lzrOVOqZN71LQVupIo1xp0dIoRrEVqe6H/WO9MYWum0inwGy63LOu1+Wxhkj4YGAXrWsocRtfzSo2asrfINC2KeuUR4UnWsWfV4PZuIv54DWSfx7lcEQaSr21dx1rystldp2e8aGlF/7kpdb/aEDeLAUZl9VDkHYs Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: X-Spam-Checker-Version: SpamAssassin 4.0.1 (2024-03-26) on aws-us-west-2-korg-listserv-alma10-1 On 10/19/26 08:45, Vitaly Wool wrote: > > >> On Oct 18, 2026, at 6:15 PM, Harry Yoo wrote: >> >> On Sun, Oct 18, 2026 at 06:03:15PM +0200, Vitaly Wool wrote: >>>>> How about we take my patch [1] instead since >>>>> it isn't prone to this bug and is a nice optimization to the existing >>>>> mempool_resize() at the same time? >>>> >>>> It is not a good idea to squeeze a bug fix and an optimization >>>> into one patch. >>> >>> Generally speaking, yes. But that patch had been submitted before the fix >>> popped up, so there was no sqeezing per se. >> >> I mean the patch you've submitted does two things (wihch is not good). >> >> It should be split into two patches that 1) fixes the bug and 2) >> optimizes it. > > I don’t think this is a fair statement. I would say that the patch I’ve > submitted improves mempool_resize() to be rid of unnecessary > reallocations and data copying, and that (improved) implementation is > *not* prone to the race found in the previous version of this function. But it makes the code more complex: 2 files changed, 28 insertions(+), 16 deletions(-) without an in-tree use case. > ~Vitaly